This application claims the priority of German application 197 15 748.3, filed Apr. 16, 1997, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a device for monitoring the air conditioning of a motor vehicle. The device is advantageously used, for example, in motor vehicles with electric or hybrid drives. The term "air conditioning," for the sake of simplicity, will be understood in this document to refer both to the function of a simple heating system, as well as the function of an air conditioning system with both heating and cooling functions.
Modern vehicle air conditioning systems of today are usually controlled by complicated electronics (in accordance with the selection of various input parameters, such as the required interior temperature and the blower speed), and then regulated electronically. Air conditioning comfort is a significant importance in such systems. An air conditioning system of this type, which is especially suitable for electric vehicles as well, is described in the article by R. Burk, H.-J. Krau.beta., and M. Lohle entitled "Integral Air Conditioning System for Electric Automobiles," ATZ Automobiltechnische Zeitschrift, volume 94, No. 11, 1992, page 582.
In German patent document DE 195 09 495 C1, a method for controlling the ventilation of a vehicle interior is disclosed which is concerned, in particular, with switching automatically between regulating fresh air and regulating recirculated air. This document discloses a method of interrupting air recirculation regulation by fresh air operating phases (even if additional regulation recirculation conditions are provided), in order to prevent the vehicle windows from fogging and to prevent the interior of the vehicle from being deprived of oxygen. The switch between fresh air and recirculated air operation can be made as a function of the operating state of an associated air conditioning system, the set difference between the outside temperature and the inside temperature and/or the vehicle speed. It is also known from this article, in conjunction with the additional prior art cited therein, that the switch between regulating fresh air and recirculated air can be made as a function of the pollutant concentration inside and outside the vehicle. Here, the respective pollutant concentration is detected via a suitably positioned pollutant sensor. With a higher pollutant concentration outside, the regulation of recirculated air is activated and, as an additional measure, a provision can be made to switch back to regulating fresh air when the pollutant concentration inside the vehicle is higher than the pollutant concentration outside the vehicle.
As a result of the comfort-oriented design of modern air conditioning systems and their operating interfaces, the user is frequently unaware of the extent to which heating and/or air conditioning affects fuel consumption and the health of the occupants. Economical fuel consumption plays a particular role (as far as the range of the vehicle in concerned), especially in vehicles with electric or hybrid drives. One health-relevant aspect (for example) is that when an inside temperature setpoint is selected by the user that differs considerably from the outside temperature, health problems can develop (for example colds, dried-out mucous membranes, and so on).
Hence, it is an object of the present invention to provide a vehicle air conditioning monitoring device which is able to monitor the vehicle air conditioning (based on health and fuel-consumption conditions) and to inform the user of the corresponding state of the air conditioning.
This and other objects and advantages are achieved by providing a vehicle air conditioning monitoring device which serves (in particular) to avoid adverse effects on the health of the vehicle occupants as a result of a temperature in the vehicle interior that differs excessively from the outside temperature. To accomplish this, the monitoring device calculates the difference between the outside temperature and the inside temperature (each detected by sensors), and compares them with a preset temperature differential warning value. The warning value can variably be set via corresponding curves that can depend on other parameters, for example, atmospheric humidity and outside and inside temperature. If the difference between the measured temperatures exceeds this temperature differential warning value, the device provides corresponding temperature difference warning information to the user. This enable the user to react in a suitable manner in order to prevent undesirable health consequences.
In another embodiment of the present invention, the monitoring device is designed, in particular, for detecting a level of atmospheric humidity in the vehicle interior that is too low and therefore unhealthy. The monitoring device also further indicates the unhealthy environment to the user in an adequate amount of time (by generating corresponding atmospheric humidity warning information), so that the occupant can make the appropriate adjustments.
In yet another embodiment of the current invention, the vehicle air conditioning (based on the disadvantageous consequences of high pollutants) monitors concentrations of pollutants in the air which the vehicle occupants breathe. For this purpose, information about the pollutant concentrations inside and outside the vehicle are supplied by suitably positioned pollutant sensors. This information is usable (if necessary) in the conventional way to switch the air conditioning system to regulating recirculated air (with high pollutant concentrations outside), or to switch to regulating fresh air (with high pollutant concentrations) in the vehicle interior. In addition to switching between operating modes (i.e., fresh air or reciculated air), the monitoring device also uses the pollutant concentration information to generate information related to whether or not interrupting travel (when both pollutant concentrations are above a suitably preselected pollutant concentration warning value) is advisable. This travel interruption recommendation information indicates to the user that, in the present situation, interrupting the journey is recommended because the driving reliability of the driver can no longer be guaranteed because of, for example, high pollution concentrations in the air.
In still another embodiment if the present invention, the vehicle air conditioning monitoring device is specially designed for use in vehicles with electric or hybrid drives to determine the vehicle range remaining as a function of the interior temperature desired by the user. Vehicles of this type are traditionally designed for the lowest possible energy consumption, so that operation of the air conditioning system has a significant influence on the total energy balance of the vehicle. Considering this, the monitoring device provides the driver with information about the anticipated range of the vehicle by taking into account the influence of the operating state of the air conditioning system, the selected interior temperature setpoint, and the other range-relevant information, which it obtains from a vehicle system controller. This information includes, for example, information about the charge state of a storage device (for electrical energy for the vehicle drive), and/or the amount of fuel remaining.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing.